Bearing spacer and housing

ABSTRACT

An exemplary center housing rotating assembly includes a turbine wheel ( 260 ); a compressor wheel ( 240 ); a center housing ( 210 ) that includes a through bore ( 215 ), extending from a compressor end to a turbine end along a bore axis, and a recess ( 217 ), adjacent the bore, in a plane orthogonal to the bore axis; a bearing assembly ( 230 ) positioned in the bore that includes a keyway ( 233 ); and an anti-rotation component ( 280 ) seated in the recess and at least partially in the keyway to restrict rotation of the bearing assembly in the bore. Various other exemplary devices, systems, methods, etc., are also disclosed.

TECHNICAL FIELD

Subject matter disclosed herein relates generally to turbomachinery forinternal combustion engines and, in particular, to techniques forlocating a bearing assembly in a bore of a turbocharger.

BACKGROUND

A conventional turbocharger typically relies on a center housingrotating assembly (CHRA) that includes a turbine wheel and a compressorwheel attached to a shaft rotatably supported by a bearing assemblylocated in a bore of a center housing. A typical bearing assembly orbearing cartridge includes an outer race and an inner race, configuredto receive a shaft, where the outer race and the inner race areseparated by rolling elements such as ball bearings.

In most CHRAs, a so-called “locating mechanism” restricts movement of abearing assembly in the bore of the center housing. Various conventionallocating mechanisms rely on radial insertion of a locating pin in anopening of an outer race of a bearing assembly. Such a mechanismrestricts radial and/or axial movement of the bearing assembly androtation of the outer race yet allows the inner race to spin freely.Additionally, such a mechanism allows for some radial movement of abearing assembly, usually within defined clearances that fill withlubricant during operation to form a “squeeze film” that acts to dampvibration and noise. In such a CHRA, the degrees of radial and axialfreedom may be chosen to be of particular magnitude or magnitudesdepending on various goals.

Various issues can arise with locating mechanisms that rely on a radiallocating pin to locate a bearing assembly. For example, during operationof a turbocharger, significant axial loads can be generated that thrustthe turbocharger shaft and associated components toward the compressorend or toward the turbine end of the turbocharger CHRA, which, in turn,can be transferred from the bearing assembly to the radial locating pin.Such forces make pin strength an important design factor. Another issuepertains to axial stack-up of components (e.g., how well do thecomponents of a CHRA stack and how does this stacking affect operationand wear). In general, a locating mechanism that relies on a radiallocating pin does not provide advantages with respect to axial stacking;indeed, the nature of the pin and the outer race opening introducegeometric and operation concerns that can be disadvantageous.

More generally, a locating mechanism, such as the aforementioned radialpin locating mechanism, can be described in terms of “key/keyway pairs”that involve male (key) and female (keyway) components that act tolocate an outer race of a bearing assembly. In such key/keyway-basedlocating mechanisms, frictional contact between key and keywaycomponents should remain low (1) to allow a bearing assembly to movefreely in the radial plane (i.e., within its squeeze film) and (2) tolimit wear between the keyway components.

Additionally, in a CHRA, to maximize efficiency and reduce powerloss,frictional contact between components should be minimized. Forturbochargers, the one source of powerloss stems from the bearingsystem. As described herein, various exemplary locating mechanisms canreduce or alleviate issues associated with locating mechanisms that relyon radial pins. For example, by reducing friction, such exemplarymechanisms can reduce powerloss and thereby improve efficiency andperformance of turbocharged internal combustion engines.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the various methods, devices, systems,arrangements, etc., described herein, and equivalents thereof, may behad by reference to the following detailed description when taken inconjunction with the accompanying drawings wherein:

FIG. 1 is a diagram of a turbocharger and an internal combustion engine.

FIG. 2 is a cutaway perspective view of an exemplary turbocharger, alonga plane defined by a line labeled A-A, which includes an anti-rotationmechanism for an outer race of a bearing assembly.

FIG. 3 is an end view of the turbocharger of FIG. 2 along a planedefined by a line labeled B-B, which includes the anti-rotationmechanism; FIG. 3 also shows an example of a variation of theanti-rotation mechanism.

FIG. 4 is a cross-sectional view of the turbocharger of FIG. 2, alongthe plane defined by the line A-A, and an enlarged cross-sectional view,along a plane defined by a line labeled C-C in FIG. 2, which includesthe anti-rotation mechanism.

FIG. 5 is a cross-sectional view of a turbocharger and a cross-sectionalview of a plate with integral key components of an anti-rotationmechanism, along a plane defined by a line labeled D-D.

FIG. 6 is a plan view and a side view of the plate of FIG. 5.

FIG. 7 is a plan view and a cross-sectional view of a bearing assemblyof the turbocharger of FIG. 5, along a plane defined by a line labeledE-E in FIG. 7.

FIG. 8 is a plan view and a side view of the plate of FIG. 6 and thebearing assembly of FIG. 7.

FIG. 9 is a plan view and a side view of a plate and the bearingassembly where the plate includes a keyway and the bearing assemblyincludes a key.

DETAILED DESCRIPTION

Turbochargers are frequently utilized to increase output of an internalcombustion engine. Referring to FIG. 1, a conventional system 100includes an internal combustion engine 110 and a turbocharger 120. Theinternal combustion engine 110 includes an engine block 118 housing oneor more combustion chambers that operatively drive a shaft 112. As shownin FIG. 1, an intake port 114 provides a flow path for air to the engineblock 118 while an exhaust port 116 provides a flow path for exhaustfrom the engine block 118.

The turbocharger 120 acts to extract energy from the exhaust and toprovide energy to intake air, which may be combined with fuel to formcombustion gas. As shown in FIG. 1, the turbocharger 120 includes an airinlet 134, a shaft 122, a compressor 124, a turbine 126, a housing 128and an exhaust outlet 136. The housing 128 may be referred to as acenter housing as it is disposed between the compressor 124 and theturbine 126. The shaft 122 may be a shaft assembly that includes avariety of components.

Referring to the turbine 126, such a turbine optionally includes avariable geometry unit and a variable geometry controller. The variablegeometry unit and variable geometry controller optionally includefeatures such as those associated with commercially available variablegeometry turbochargers (VGTs). Commercially available VGTs include, forexample, the GARRETT® VNT™ and AVNT™ turbochargers, which use multipleadjustable vanes to control the flow of exhaust across a turbine. Anexemplary turbocharger may employ wastegate technology as an alternativeor in addition to variable geometry technology.

FIG. 2 shows a cross-sectional perspective view of an exemplaryturbocharger 200 where a plane defined by a line A-A, a plane defined bya line B-B and a plane defined by a line C-C are shown. The A-A plane isthe cross-sectional plane of the view of FIG. 2 whereas a view for theB-B plane is shown in FIG. 3 and a view for the C-C is shown in FIG. 4.

The turbocharger 200 serves as a non-limiting example to describevarious exemplary devices, methods, systems, etc., disclosed herein. Theturbocharger 200 includes a center housing 210, a shaft 220, a bearingassembly 230, a compressor section 240, a turbine section 260 and alocating mechanism that includes a plate 270 and an anti-rotationcomponent 280.

The compressor section 240 includes a compressor housing 241 that housesa compressor wheel 242 that includes a hub 243 and blades 244. Theturbine section 260 includes a turbine housing 261 that houses a turbinewheel 262 that includes a hub 263 and blades 264. As shown, thecompressor wheel 242 and the turbine wheel 262 are operably connected tothe shaft 220. The shaft 220 may be made of multiple components thatform a single operable shaft unit. The compressor wheel 240, the turbinewheel 260 and the shaft 220 have an axis of rotation substantiallycoincident with the z-axis. The center housing 210 includes a bore 215that is configured to receive a bearing assembly 230, which, in turn,receives the shaft 220 and allows for rotation of the shaft 220 aboutthe z-axis.

As shown in the example of FIG. 2, the center housing 210 includeslubricant pathways to allow lubricant to flow to and from the bearingassembly 230. Specifically, the housing 210 includes a lubricant inlet212 and a lubricant outlet 216. Intermediate the lubricant inlet 212 andthe lubricant outlet 216 are various features that define one or morelubricant flow paths. An axial lubricant path 213 is configured todirect lubricant from the lubricant inlet 212 to openings along the bore215 of the center housing 210. As configured, lubricant can flow withinthe center housing 210 (e.g., enter the bearing assembly 230) andultimately drain from the housing via the lubricant outlet 216 (e.g.,due to gravity).

With respect to the locating mechanism, four components or featuresthereof are involved: (1) a stop 211 of the center housing 210,positioned at a turbine end of the bore 215; (2) the plate 270 attachedto the center housing 210, positioned at a compressor end of the bore213; (iii) a recess in the center housing 210 (see FIGS. 3 and 4); and(iv) the anti-rotation component 280, which may be positioned at any ofa variety of locations along the length of an outer race of a bearingassembly. In the example of FIG. 2, the anti-rotation component 280 isshown as being positioned at the compressor end of the bore 215 andadjacent a compressor end of the bearing assembly 230 where at least aportion of the anti-rotation component 280 is seated in a recess of thecenter housing 210.

FIG. 3 shows a view of the turbocharger 200 from the B-B plane.Specifically, FIG. 3 shows the center housing 210, a recess 217 in thecenter housing 210, the shaft 220, the bearing assembly 230 and theanti-rotation component 280. The bearing assembly 230 includes an outerrace 232, an inner race 234 and rolling elements 236. In the view ofFIG. 3, the axial lubricant path 213 and the bore 215 are shown alongwith four apertures to receive bolts or the like to attach the plate 270to the center housing 210.

In the example of FIG. 3, the outer race 232 includes a notched orkeyway portion 233 that cooperates with a key portion of theanti-rotation component 280. As shown, the center housing 210 has abeveled edge at the compressor end of the bore 215 and the recess 217 ispositioned adjacent the bore 215. The anti-rotation component 280 isseated in the recess 217, which is configured to limit rotation of theanti-rotation component 280. Specifically, the recess 217 and theanti-rotation component both have an oblong shape where that of therecess 217 is slightly larger in widthwise dimension than acorresponding dimension of the anti-rotation component 280, which whileallowing for some movement, restricts excessive movement of theanti-rotation component 280 in the recess 217.

In the example of FIG. 3, the anti-rotation component 280 has an outerradius R_(C) and a width W_(C) while the recess 217 has an outer radiusR_(R) and a width W_(R). As shown, these 2D dimensions of the recess 217exceed those of the anti-rotation component 280. While FIG. 3 shows aparticular configuration and shape, as described herein, otherconfigurations and shapes may be used (see, e.g., the example 290). Theexample of FIG. 3 also shows an offset between an axis of rotation ofthe shaft 220 and an axis of rotation of the anti-rotation component280. In this example, the anti-rotation component 280, as received bythe recess 217, limits rotation of the outer race 232 about the axis ofrotation of the shaft 220. The amount of rotation of the outer race 232may be determined wholly or in part by one or more factors such asdimensions of the recess 217, dimensions of the anti-rotation component280, dimensions of the keyway 233, etc.

In the example of FIG. 3, a point or points of contact exist between thekeyway 233 and an edge of the anti-rotation component 280. Further, apoint or points of contact exist between the anti-rotation component 280and, for example, an axial wall of the center housing 210 that definesthe recess 217. In the example of FIG. 3, contact between theanti-rotation component 280 and the center housing 210 counteract forceexerted by contact between the outer race 232 and the anti-rotationcomponent 280. Further, the anti-rotation component 280 as configured inFIG. 3, can restrict rotation of the outer race 232 in either clockwiseor counter-clockwise directions. To do so, the anti-rotation component280 can rotate (e.g., clockwise or counter-clockwise about an axis) asseated in the recess 217.

As a key with restricted movement, the anti-rotation component 280, whenseated at least partially in the keyway portion 233 of the outer race232, restricts rotational movement of the outer race 232. Hence, theaforementioned features restrict rotation of the bearing assembly 230 inthe bore 215 of the center housing 210 without resorting to a radiallocating pin. Further, as the anti-rotation component 280 is covered bythe plate 270, axial thrust forces received by the anti-rotationcomponent 280 (if any) can be transmitted to the plate 270.Specifically, depending on the relationship between the depth of thekeyway 233, the recess 217 and the thickness of the anti-rotationcomponent 280, it is possible to ensure that no significant axial thrustforces are transmitted to the anti-rotation component 280. In such aconfiguration, the anti-rotation component 280 has no or littledetrimental effect as to axial stacking of the components of a CHRA.

FIG. 3 also shows an exemplary anti-rotation mechanism 290 where ananti-rotation component 296 (key) includes a curved edge (e.g., convex)and where a bearing 291 include an outer race 292 with a curved edge 293(e.g., concave, defining a keyway). Further, the mechanism 290 includesa recess 297 having a shape (e.g. boundary) that acts to prevent orlimit rotation of the anti-rotation component 296. In the examples ofFIG. 3, the anti-rotation mechanisms may be referred to as includingkey/keyway pairs.

As described herein, an exemplary anti-rotation mechanism includes afeature associated with an outer race and another complimentary featurewhere the two features act as a key and keyway pair to limit rotation ofthe outer race.

FIG. 4 shows a cross-sectional view (along the A-A plane) of some of thecomponents of the turbocharger 200 of FIG. 2 and an enlargedcross-sectional view of the anti-rotation component 280 in along the C-Cplane as indicated in FIG. 2.

In the C-C plane view, the anti-rotation component 280 is shown asincluding a head portion 282 and a shaft portion 284. In the example ofFIG. 4, the head portion 282 is seated in the recess 217 while the shaftportion 284 is seated in an axial bore 218. As described herein, theshaft portion 284 may loosely fit, tightly press fit, thread fit, etc.,in the axial bore 218.

As shown in the C-C plane view, the plate 270 covers at least a part ofthe head portion 282 of the anti-rotation component 280. As mentioned,if axial thrust forces are received by the anti-rotation component 280,they may be transferred to the plate 270 (e.g., which may be referred toas a cover plate).

While not shown in the views of FIGS. 2, 3 and 4, the plate 270 caninclude apertures that allow for use of blots or the like to attach theplate 270 to the center housing 210. As shown in FIG. 4, another plate250, referred to as a compressor wheel plate, is seated over the plate270. In the example of FIG. 4, disposed between the compressor plate 250and the locating plate 270 is a thrust collar 255. As shown, the thrustcollar 250 can receive axial thrust forces from the shaft 220 (or innerrace 234) and transfer these forces to the compressor plate 250. Thrustforces received by the outer race 232 can be transferred to the locatingplate 270, which is attached to the center housing 210. Again, invarious configurations, axial thrust received by the anti-rotationcomponent 280 may be minimal or minimized.

As indicated in the C-C plane view of FIG. 4, the keyway feature 233 ofthe outer race 232 doe not interfere with the raceway of the innersurface of the outer race 232.

As described herein, another exemplary anti-rotation mechanism relies ona plate that includes or seats one or more anti-rotation keys forreceipt by one or more corresponding keyways (e.g., notches) in an outerrace of a bearing assembly. FIG. 5 shows cross-sectional views ofvarious components of an exemplary CHRA 500 including a center housing510, a shaft 520, a bearing assembly 530, a thrust collar 555 and aplate 570. The center housing includes a stop 511 (e.g., an opening withan arc or a diameter smaller than the outer diameter of an outer race),a lubricant inlet 512, a lubricant well 513, a bore 515 and a lubricantoutlet 516. The bearing assembly 530 includes an outer race 532, aninner race 534 and various rolling elements 536 disposed therebetween,which allows the inner race 534 to spin freely. As shown the inner race534, which may be a multi-component inner race, receives a shaft 520which attaches to a turbine wheel at a turbine end (right side) and acompressor wheel at a compressor end (left side).

In the example of FIG. 5, the stop 511 and the plate 570 act to axiallylocate the bearing assembly 530 in the bore 515 of the center housing510. Specifically, the stop 511 restricts axial movement of the outerrace 532 at the turbine end of the bore 515 while the plate 570restricts axial movement of the outer race 532 at the compressor end ofthe bore 515. In the cross-sectional view along a plane defined by aline D-D, the plate 570 is shown as being attached to the center housing510 via a bolt 590 that is inserted into the center housing 510 via anaperture 572 of the plate 570. The center housing 510 can includevarious openings with threads or other features to receive the bolt 590or other attachment component (see, e.g., items 219 in the example ofFIG. 3).

Details of the anti-rotation mechanism associated with the plate 570 areshown in FIGS. 6, 7 and 8. Specifically, FIG. 6 shows features of theplate 570, FIG. 7 shows features of the bearing assembly 530 and FIG. 8shows how features of the plate 570 and the bearing assembly 530cooperate to restrict rotation of the outer race 532 of the bearingassembly 530.

FIG. 6 shows a plan view and a side view of the plate 570 of FIG. 5along with a central z-axis for reference (see the z-axis of rotation ofthe shaft 520 in FIG. 5). In the example of FIG. 6, the plate 570includes a cutout spanning angle X about the z-axis, a plurality ofapertures 572, an arced notch 574 at a radius R_(N), an opening at aradius R_(O), and two keys 578, 578′ positioned at an angle Y about thez-axis.

FIG. 7 shows a side view and a cross-sectional view of the exemplarybearing assembly 530 of FIG. 5. In the side view, keyways 535 and 535′are shown in the outer race 532. In the views of FIG. 7, the keyways535, 535′ are shown as being inset from an outer diameter of the outerrace 532. Specifically, an inset diameter is labeled “D_(Inset)”, whichis less than an adjacent outer diameter. In the example of FIG. 7, theopposing end of the bearing assembly 530 does not include a section withan inset diameter. As shown in FIG. 5, the opposing end cooperates withthe stop 511 of the center housing 510 to restrict axial movement of thebearing assembly 530.

FIG. 8 shows a plan view and a side view of the plate 570 and thebearing assembly 530. In FIG. 8, one of the keys 578, 578′ of the plate570 is shown as being received by a respective one of the keyways ornotches 535, 535′ of the bearing assembly 530. In such a manner,rotation of the outer race 532 of the bearing assembly 530 is restrictedwhen positioned in the bore 515 of the center housing 510 as shown inFIG. 5.

In the examples of FIGS. 5, 6, 7 and 8, keys can be integral to a thrustplate while corresponding keyways can be integral to an outer race of abearing assembly. As explained with respect to FIG. 7, the keyways canbe recessed from the OD of the outer race such that the centerless grindof the bearing OD does not encounter any discontinuities along the OD,near the raceway. If there were discontinuities on the OD during thecenterless grind operation, machining imperfections on the OD would becreated and subsequently transferred to the raceway grind (which isregistered off the OD).

As shown in FIG. 7, the keyways 535, 535′ are located outboard of theraceway for the rolling elements 536. A key received by each of thekeyway 535, 535′ may be configured to avoid contact axially (e.g., at anaxial wall of a keyway). In such an example, a key only contacts alateral wall or walls of a keyway (e.g., in the azimuthal direction). Asdescribed herein, a keyway may be undercut on the outer diameter of anouter race of a bearing assembly and formed in a manner that avoidsinterference with a raceway (e.g., as bound by a low shoulder (faceside) and a high or “deep” shoulder (back side)). For example, a “ballband” may be formed by a ball riding over an edge of a raceway (e.g.,which may be possibly caused by thrust forces). Hence, in variousexamples, one or more keyways in an outer race are formed using acenterless grind operation where the one or more keyways are positionedto avoid risk of raceway/rolling element damage (e.g., via thrust,misalignment, loose fit, etc.). As described herein, a keyway may be anOD relief of an outer race (e.g., for friendliness to a centerless grindoperation).

FIG. 9 shows a plan view and a side view of a plate 970 and a bearingassembly 930. In FIG. 9, the plate 970 includes keyways 978, 978′ and anouter race 932 of the bearing assembly 930 includes keys 935, 935′. Thekeys 935, 935′ of the outer race 932 are shown as being received by therespective keyways 978, 978′ of the plate 970. In such a manner,rotation of the outer race 932 of the bearing assembly 930 is restrictedwhen positioned in a bore of a center housing.

In various examples, a plate may include one or more keys and one ormore keyways. In various examples, an outer race of a bearing mayinclude one or more keys and one or more keyways. In such examples, akey is received by a keyway. Various examples exist where depending onnumber of keys and keyways, some keyways may be unfilled upon assembly.For example, consider an outer race with four keyways and a plate withtwo keys where two of the keyways remain unfilled upon assembly. Invarious examples, a key/keyway pair (or pairs) provides a proscribedamount of freedom for a bearing assembly to move radially in a squeezefilm damper (e.g., as formed between the outer race and bore of ahousing).

As described herein, features of an outer race of a bearing assembly mayact to locate the outer race with respect to one or more features of ahousing. For example, the bearing assembly 530 of FIG. 5 includeslubricant jets to direct lubricant from the lubricant well 513 to therolling elements 536. In such an example, one or more key/keyway pairsmay act to locate the lubricant jets with respect to the lubricant well513. In general, such locating may be referred to as azimuthal locatingthat establishes a relationship between an asymmetrical outer race and ahousing (e.g., in an azimuthal direction, defined by a longitudinal axisof a bore of the housing).

As described, the exemplary locating mechanism of FIGS. 5, 6, 7, 8 and 9allows for efficient machining of keys and keyways that act to limitrotational freedom of an outer race while maintaining low frictionenabling radial freedom within its lubricant film and beneficial wearproperties between key/keyway pairs.

As described herein, an exemplary method for locating an outer race of abearing in a bore of a housing includes inserting the bearing in thebore of the housing; attaching a plate to the housing to at leastpartially axially locate the bearing in the bore of the housing; andrestricting rotation of the outer race of the bearing in the bore of thehousing by contacting an axially extending key and a keyway. In such amethod, the plate may include the key and the bearing may include thekeyway or, alternatively, the outer race of the bearing may include thekey and the plate may include the keyway. In such a method, thecontacting optionally azimuthally locates one or more lubricant jets ofthe outer race of the bearing with respect to a lubricant well of thehousing. In such a method, the plate may receive axial thrust forceswithout an axial end of the key contacting an axial end of the keyway(e.g., to avoid wear on the key and/or keyway).

Although some exemplary methods, devices, systems, arrangements, etc.,have been illustrated in the accompanying Drawings and described in theforegoing Detailed Description, it will be understood that the exemplaryembodiments disclosed are not limiting, but are capable of numerousrearrangements, modifications and substitutions without departing fromthe spirit set forth and defined by the following claims.

What is claimed is:
 1. A center housing rotating assembly comprising: aturbine wheel (260); a compressor wheel (240); a center housing (210)that comprises a through bore (215), extending from a compressor end toa turbine end along a bore axis, and a recess (217), adjacent the bore,in a plane orthogonal to the bore axis; a bearing assembly (230)positioned in the bore that comprises a keyway (233); and ananti-rotation component (280) seated in the recess and at leastpartially in the keyway to restrict rotation of the bearing assembly inthe bore.
 2. The center housing rotating assembly of claim 1 furthercomprising a cover plate (270) attached to the center housing whereinthe cover plate covers at least part of the anti-rotation component. 3.The center housing rotating assembly of claim 1 wherein theanti-rotation component comprises a head portion (282) and a shaftportion (284).
 4. The center housing rotating assembly of claim 3wherein the center housing comprises an axial bore (218) configured toreceive the shaft portion of the anti-rotation component.
 5. The centerhousing rotating assembly of claim 1 wherein the anti-rotationcomponent, as seated in the recess, is configured to rotatecounter-clockwise responsive to clockwise rotation of the bearingassembly and to rotate clockwise responsive to counter-clockwiserotation of the bearing assembly.
 6. The center housing bearing assemblyof claim 1 wherein the anti-rotation component comprises an axis ofrotation offset from the bore axis.
 7. The center housing bearingassembly of claim 6 wherein a sum of a maximum outer diameter of thebearing assembly and a minimum widthwise dimension of the anti-rotationcomponent exceed the offset.
 8. The center housing bearing assembly ofclaim 1 wherein the recess comprises a recess positioned at a compressorend of the center housing.
 9. The center housing bearing assembly ofclaim 8 wherein the recess comprises a depth sufficient to seat theanti-rotation component below a compressor end surface of the centerhousing.
 10. The center housing bearing assembly of claim 1 wherein theanti-rotation component does not receive axial thrust forces from thebearing assembly.